Field
This disclosure relates to treatment of orthopedic tissue.
Description of the Related Art
The prostate is a walnut-sized gland located beneath the bladder and in front of the rectum. The urethra passes through the prostate to the bladder neck. Commonly, as a man ages, the prostate begins to grow and this growth often results in the prostate squeezing the urethra within it. This proliferation of tissue in the prostate gland is known as benign prostatic hyperplasia (BPH). BPH causes urination problems when an enlarged prostate presses against the urethra narrowing the canal. BPH is estimated to affect over fifty percent of men over the age of sixty.
Approximately one-third of prostate tissue is anterior to the urethra and consists of fibromuscular tissue physiologically related to the urethra and bladder. Approximately two-thirds of prostate tissue is posterior to the urethra and consists of glandular tissue. BPH involves bilateral nodular expansion of prostate tissue in a transition zone between the fibromuscular tissue and the glandular tissue. Without treatment, BPH obstructs the urethra to cause a slow or interrupted urinary stream, nocturia, increased frequency of urination, a sense of urinary urgency, and incontinence. Occasionally, BPH is also responsible for more severe problems including uraemia, hydronephrosis, and urinary tract infections. Uraemia is retention in the bloodstream of waste products normally excreted in the urine. Hydronephrosis is the dilation of the branches of the pelvic cavity and the kidney, caused by an accumulation of urine resulting from obstruction of normal outflow.
Systems and methods exist to treat BPH. These include drug therapy, non-surgical procedures, and surgical procedures (i.e., prostatectomy).
Drugs often have side effects and must be taken long-term for continued effectiveness.
Non-surgical (without mechanical cutting) conventional BPH procedures, such as thermotherapy, use various forms of energy (radiofrequency, microwave, ultrasound, etc.) to ablate the prostate tissue. The application of energy is usually overbroad and results in ablation-induced collateral damage and necrosis (cell death) of healthy urethral tissue. These non-mechanical energy delivery devices alleviate symptomatic pressure and widen the constricted urethra by coring out a new urethral channel formed by scar tissue. However, overly aggressive scar tissue proliferation occasionally results in some individuals, and can have side effects including seminal vesicle blockage (leading to reverse ejaculation, dry climax, etc.) and an increase in volume that creates pressure and undermines the achievement of volume reduction in the prostate. Other technologies such as TURP (TransUrethral Resection of the Prostate) and LASER (Light Amplification by Stimulated Emission of Radiation) also destroy healthy tissue including important muscles at the bladder neck. The bladder neck is a common target for treatment. The widening with both TURP and LASER damage the bladder's muscular structure that can lead to bladder incontinence and can also reduce or eliminate the bladder neck's ability to constrict upon sexual stimulation/ejaculation allowing the ejaculate to travel in reverse into the male's bladder, thus yielding him with reverse ejaculation.
Conventional surgical systems for removal of the prostate (prostatectomy) are bulky and expensive and their use generally results in the loss of fertility. Prostatectomy is typically performed as an in-patient procedure requiring general anesthesia, a longer term hospital stay, and a significant recovery time before a patient returns to work.
Thus, the common approaches to BPH treatment are not minimally invasive and result in trauma to and the removal of the urethral lining, crucial bladder neck musculature, and the prostate's capsule, as well as an unnecessarily large section of the prostate or the entire prostate. Common approaches damage the urethra which results in scar tissue that may occlude the seminal vesicle with the reduction or potential loss of fertility and possibly increase the potential for reverse ejaculation, resulting from the blockage and reduced smooth lining of a natural urethra. Damage to the smooth lining of the urethra caused by these approaches results in increased pain, discomfort, extended catheterization, additional time off from work (recovery), increased dependence on pain medications and extended (and expensive) in-patient hospital stays.
Recent prostate treatment probes have focused on newer energy therapies while an understanding of how to precisely control them to selectively remove tissue remains to be mastered. Mechanical cutting/coring of prostate tissue has remained largely unconsidered.
Another important consideration in BPH treatment is to address the problem early. This is in contrast to the “watchful waiting” approach that typically coincides with drug therapy while putting off surgery until symptoms become unbearable and conclusively demonstrate irresponsiveness to drugs. The easier and safer the surgical procedure becomes the less it is something to be put off and avoided. There are significant benefits to be obtained in early intervention in the form of preserved bladder muscle tone and function. The longer an individual with a developing hypertrophic prostate waits before having surgery (to remove the hypertrophic portion) the more likely it is the hypertrophic tissue will begin to obstruct the bladder neck which leads to all sorts of complications as the bladder reacts to try and achieve a higher pressure to pass fluid through the constricted neck. These complications include: permanent loss of detrusor contractile ability, involuntary detrusor contractions, partial denervation of the bladder smooth muscle, bladder irritability and instability, early termination of voiding, intermittency of the urinary stream, higher residual urine volume, loss of bladder compliance, and overall bladder mass increase with less muscle tone and more collagen deposition. As the body reacts to the obstruction the internal and external sphincters can also be damaged and worn down. The loss of involuntary muscle response that accompanies damage to the internal sphincter generally cannot be reacquired through training (whereas training is sometimes effective to reverse damage to voluntary muscles). Thus, damage to the internal sphincter from waiting too long for surgery and/or from other less selective procedures can cause irreversible reverse ejaculation.